Section 5: Kepler elements, nodes, apsides and orbital periods

Source: R/RcppExports.R

Functions for: determining Kepler elements, nodes, apsides and orbital periods

swe_nod_aps_ut(jd_ut, ipl, iflag, method)

swe_nod_aps(jd_et, ipl, iflag, method)

swe_get_orbital_elements(jd_et, ipl, iflag)

swe_orbit_max_min_true_distance(jd_et, ipl, iflag)

Arguments

jd_ut

UT Julian day number as double (day)

ipl

Body/planet as integer (SE$SUN=0, SE$MOON=1, ... SE$PLUTO=9)

iflag

Computation flag as integer, many options possible (section 2.3)

method

Method as integer (SE$NODBIT_MEAN=0, SE$NODBIT_OSCUN=1,, SE$NODBIT_OSCU_BAR=4, SE$NODBIT_FOPOINT=256)

jd_et

ET Julian day number as double (day)

Value

swe_nod_aps_ut returns a list with named entries:

return status flag as integer, xnasc ascending nodes as numeric vector,

xndsc descending nodes as numeric vector, xperi perihelion as numeric vector, xaphe aphelion as numeric vector and serr error message as string

swe_nod_aps returns a list with named entries:

return status flag as integer, xnasc ascending nodes as numeric vector,

xndsc descending nodes as numeric vector, xperi perihelion as numeric vector, xaphe aphelion as numeric vector and serr error message as string

swe_get_orbital_elements returns a list with named entries:

return status flag as integer, dret function results as numeric vector and serr error message as string

swe_orbit_max_min_true_distance returns a list with named entries:

return status flag as integer, dmax maximum distance as double,

dmin minimum distance as double, dtrue true distance as double and serr error message as string

Details

swe_nod_aps_ut()

Compute planetary nodes and apsides (perihelia, aphelia, second focal points of the orbital ellipses).

swe_nod_aps()

Compute planetary nodes and apsides (perihelia, aphelia, second focal points of the orbital ellipses).

swe_get_orbital_elements()

This function calculates osculating elements (Kepler elements) and orbital periods.

swe_orbit_max_min_true_distance()

This function calculates the maximum possible distance, the minimum possible distance and the current true distance of planet.

See also

Section 5 in http://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_nod_aps_ut(2451545,SE$MOON, SE$FLG_MOSEPH,SE$NODBIT_MEAN)
#> $return
#> [1] 0
#> 
#> $xnasc
#> [1] 1.250406e+02 3.476104e-13 2.460922e-03 0.000000e+00 0.000000e+00
#> [6] 0.000000e+00
#> 
#> $xndsc
#> [1] 3.050406e+02 2.439083e-13 2.671325e-03 0.000000e+00 0.000000e+00
#> [6] 0.000000e+00
#> 
#> $xperi
#> [1] 83.464332724 -3.419715015  0.002428485  0.000000000  0.000000000
#> [6]  0.000000000
#> 
#> $xaphe
#> [1] 2.634643e+02 3.419715e+00 2.710625e-03 0.000000e+00 0.000000e+00
#> [6] 0.000000e+00
#> 
#> $serr
#> [1] ""
#> 
swe_nod_aps(2451545,SE$MOON, SE$FLG_MOSEPH,SE$NODBIT_MEAN)
#> $return
#> [1] 0
#> 
#> $xnasc
#> [1] 1.250407e+02 1.105681e-13 2.460922e-03 0.000000e+00 0.000000e+00
#> [6] 0.000000e+00
#> 
#> $xndsc
#> [1]  3.050407e+02 -2.612689e-13  2.671325e-03  0.000000e+00  0.000000e+00
#> [6]  0.000000e+00
#> 
#> $xperi
#> [1] 83.464250479 -3.419723161  0.002428485  0.000000000  0.000000000
#> [6]  0.000000000
#> 
#> $xaphe
#> [1] 2.634643e+02 3.419723e+00 2.710625e-03 0.000000e+00 0.000000e+00
#> [6] 0.000000e+00
#> 
#> $serr
#> [1] ""
#> 
swe_get_orbital_elements(2451545,SE$MOON, SE$FLG_MOSEPH)
#> $return
#> [1] 0
#> 
#> $dret
#>  [1]  2.552584e-03  6.317394e-02  5.240360e+00  1.239572e+02  3.089075e+02
#>  [6]  7.286466e+01  1.466895e+02  1.504159e+02  1.485766e+02  2.195542e+02
#> [11]  7.435498e-02  1.325595e+01  7.435776e-02 -2.933903e+01  2.451534e+06
#> [16]  2.391328e-03  2.713841e-03  0.000000e+00  0.000000e+00  0.000000e+00
#> [21]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> [26]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> [31]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> [36]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> [41]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> [46]  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00  0.000000e+00
#> 
#> $serr
#> [1] ""
#> 
swe_orbit_max_min_true_distance(2451545,SE$MOON, SE$FLG_MOSEPH)
#> $return
#> [1] 0
#> 
#> $dmax
#> [1] 0.002713841
#> 
#> $dmin
#> [1] 0.002391328
#> 
#> $dtrue
#> [1] 0.002690191
#> 
#> $serr
#> [1] ""
#>